Medical diagnostic testing methods are critical screening tools for the early detection of pathological conditions. Early detection permits the identification of such conditions at a stage when successful treatment is more likely. Early treatment also frequently involves less damaging or less invasive treatment methods and decreases the impact on the patient. In addition to routine screening, diagnostic testing is also used in a variety of other applications, including biopsy analysis and monitoring the results of ongoing medical treatment.
Typical methods of analyzing samples such as medical samples for the presence of particular components can include multiple processing steps such as fixation, staining, permeabilization, in situ hybridization, and other enzymatic and/or chemical treatments, depending on the particular assays being performed.
Limitations on the amount of diagnostic information that can be obtained from a sample include the size of the sample that can be obtained and readily manipulated, the processing time required to perform multiple tests, the tolerance of the sample for multiple treatment steps without loss of signal, and the cost for performing multiple methods of analysis.
Medical samples are frequently stained using a variety of techniques known in the art. A number of staining solutions include a fixative such as an alcohol, although many also require fixation steps. Often it is desirable to obtain additional information on a variety of species which are or may be present in the sample, and/or to obtain information about smaller components such as viruses or other cellular or other species which may occur in a sample but which cannot be adequately interrogated using staining methods.
Use of more precise molecular techniques such as in situ hybridization can provide even more detailed information from a sample than staining techniques. However, in situ hybridization requires multiple tedious manipulations of a sample, involving fixation, transfer to a slide, stepwise manipulations through solution gradients, coverslipping, lengthy hybridization steps, washing, drying and other processing steps. Such methods are time consuming and require exacting care at multiple steps.
There is a need in the art for improved procedures for analyzing samples, and for compositions and articles of manufacture useful in such methods.